1. Field of the Invention
The present invention pertains to a system for monitoring the operation of one or more gas lift valves in a fluid production well and wherein the system includes sensors for detecting which gas lift valves are functioning and sensors for detecting certain properties of the produced fluid flowing in the tubing in the vicinity of one or more of the gas lift valves.
2. Background
One method of artificial lift of liquids from wells that either will not flow, or not flow at optimum rates, comprises injecting pressure gas at various points along the well production fluid tubing string to assist in "lifting" fluids to the surface. Gas lift systems usually include a plurality of spaced-apart pressure operated valves which are adapted to open at a predetermined gas pressure to admit the lift gas into the production tubing.
However, optimum lifting conditions are not always achieved after the gas lift valves have been installed due to changes in the fluid production characteristics of the well or malfunctioning of one or more of the gas lift valves, for example. If optimum gas lift operation is not being achieved in conventional gas lift systems, it is necessary to retrieve each of the gas lift valves to determine if it is functioning properly or to change the pressure conditions under which the valve is set to open. Still further, it is often necessary and desirable to determine the pressure, temperature and viscosity, for example, of the fluid being produced from the well so that certain adjustments to the operation of the gas lift system may be carried out to improve well production. The present invention overcomes some of the deficiencies and problems associated with prior art gas lift wells by providing a system for monitoring the operation of one or more gas lift valves and for transmitting information concerning the conditions of the produced fluid in the production tubing string at selected ones of the gas lift valves.